Turbine apparatus



Dec. 20, 1966 R. M- DONALDSON TURBINE APPARATUS 5 Sheets-Sheet 1 FiledMarch 4. 1965 JNVENTOR ROBERT MDONALDSON Dec. 20, 1966 M. DONALDSON 3,

TURBINE APPARATUS Filed March 4. 1965 5 Sheets-Sheet 2 msmmoaROBERIMDONALDSON ATTORN EYS Dec. 20, 1966 R. M. DONALDSON 3,

TURBINE APPARATUS Filed March 4, 1965 5 Sheets-Sheet :s

JIK/VZ-SNTZZMP. ROBERT MDONALDSOH ATTO 2. M EYS United States Patent3,292,901 TURBINE APPARATUS Robert M. Donaldson, Hampton, Va., assignorto Newport News Shipbuilding and Dry Dock Company, Newport News, Va., acorporation of Virginia Filed Mar. 4, 1965, Ser.-No. 437,244 Claims.(Cl. 253-117) The present invention relates to new and novel hydraulicturbine apparatus, and more particularly to an improved draft tubeconstruction employed with hydraulic turbines of the reaction type.

The present invention is particularly concerned with hydraulic turbineapparatus such as the turbines commonly used in hydroelectric powerplants and the like. Such turbines may be of Francis or Kaplan type andmay also include fixed vane propellor type turbines.

It is well recognized in the art that at loads above and below thedesign load of a hydraulic turbine, the liquid leaving the runner has anappreciable whirl which results in vorticity in the draft tube of theturbine, this vorticity often causing objectionable noise and vibration,instability of operation or pressure surges and power swings in thedraft tube, spiral case and penstock.

The present invention provides an arrangement wherein flow control meansis incorporated in the draft tube of the apparatus. This flow controlmeans is of such a construction as to stabilize the flow in the drafttube by reducing the vortex while at the same time not interfering withthe whirling motion of the liquid whereby the performance of the turbinewill not be appreciably affected at its design load and will besignificantly improved at loads above and below the design load. Thisimproved stabilized flow operation serves to substantially reduce thenoise, vibration, pressure surges and power swings with no appreciableloss in power or efficiency.

The flow control means includes a generally tubular or annular bodymeans which is fixedly mounted in the upper part of the draft tube andis spaced from the inner surface of the draft tube and substantiallyconcentric therewith. This body means defines a central bore formedtherethrough, and the liquid from the runner flows through the bore inthe body means and around the outer periphery of the body means inpassing downwardly through the draft tube. The axially extendingportions of the body means are oriented approximately in line with theflow of liquid from the runner when it is operating at its design loadso as to provide a minimum of interference with the whirling motion ofthe liquid.

The flow control means is also spaced a particular distance from theundersurface of the runner, this distance being within a certaincritical range of distances as related to the inner diameter of the topportion of the draft tube. The inner diameter and length of the boreextending through the body means of the flow control means is alsorelated to the inner diameter at the top portion of the draft tube suchthat such inner diameter and length of the bore must be within certaincritical ranges as related to the inner diameter at the top portion ofthe draft tube.

In one modification of the invention, the body means may comprise asubstantially cylindrical means while in another modification the bodymeans is of a substantially frusto-conical configuration having acentral bore formed therethrough. In a still further modified form ofthe invention, streamlining means is provided on the support means forthe body means, such streamlinging means being freely movable withrespect to the support means so as to automatically move into properposition for minimizing resistance and interference to the normalwhirling motion of the liquid.

A further modification of the invention includes the 3,292,901 PatentedDec. 20, 1966 above possible structural features and also contemplatesthe provision of means for introducing gas to the upper central portionof the bore provided through the body means so as to cushion the shocksand smooth out the flow of liquid through the flow control means.

An object of the present invention is to provide new and novel hydraulicturbine apparatus which substantially reduces the noise attendant withoperation thereof.

Another object is the provision of hydraulic turbine apparatus whereinvibration of the apparatus is substantially reduced.

Still another object of the invention is to provide hydraulic turbineapparatus wherein pressure surges are substantially reduced.

Yet a further object of theinvention is the provision of hydraulicturbine apparatus wherein power swings are minimized.

Yet another object of the invention is to provide hydraulic turbineapparatus wherein the performance is not appreciably affected at thedesign load and wherein considerably improved performance is provided atloads above and below the design load with no appreciable loss in poweror efficiency.

A still further object of the invention is the provision of hydraulicturbine apparatus which is quite simple and inexpensive in construction,and yet which is at the same time efiicient and reliable in operation.

Other objects and many attendant advantages of the invention will becomemore apparent when considered in connection with the specification andaccompanying drawings, wherein:

FIG. 1 is a vertical section through a portion of a hydraulic turbineincorporating the present invention;

FIG. 2 is a sectional view taken substantially along line 2-2 of FIG. 1looking in the direction of the arrows;

FIG. 3 is a sectional view taken substantially along line 3-3 of FIG. 2looking in the direction of the arrows;

' FIG. 4 is a view illustrating the flow control means disposed withinthe draft tube and illustrating the critical limits of the size andlocation of the flow control means;

FIG. 5 is a vertical section through a draft tube incorporating amodified form of the flow control means;

FIG. 6 is a sectional view taken substantially along line 6--6 of FIG. 5looking in the direction of the arrows;

FIG. 7 is a vertical section similar to FIG. 1 illustrating a furtherform of the invention;

FIG. 8 is a sectional view taken substantially along line 88 of FIG. 7looking in the direction of the arrows;

FIG. 9 is a sectional view taken substantially along line 99 of FIG. 8looking in the direction of the arrows;

FIG. 10 is a top view of a draft tube incorporating a further modifiedform of flow control means; and

FIG. 11 is a sectional view taken substantially along line 11--11 ofFIG. 10 looking in the direction of the arrows.

Referring now to the drawings wherein like reference charactersdesignate corresponding parts throughout the several views, a firstmodification of the invention is illustrated in FIGS. 1-4 inclusive andincludes a shaft 20 of a hydraulic turbine which extends through hearing22 in cover plate 24. A runner 26 is connected with the lower end ofshaft 20, this runner being shown as being of the Francis reaction type.Liquid such as water is supplied to runner 26 by way of the conventionalspiral case 28, the fiow of water being controlled by a gate comprisinga plurality of vanes 30 mounted for movement in the cover plate and in alower casing portion 32.

Water is discharged from the runner vertically downwardly into a drafttube indicated generally by reference numeral 40. The structuredescribed up to this point is 3 that of the usual Francis reaction typetubrine and further details of construction of the turbine are notconsidered necessary.

T he flow control means includes a generally annular or tubular bodymeans indicated generally by reference numeral 42, this body means inthis particular configuration comprising a substantially cylindricalring member having a bore 44 extending therethrough. Body means 42 issupported in spaced relationship from the inner surface of the drafttube and substantially concentric with the draft tube such that thelongitudinal axes of the draft tube and the body means 42 coincide withone another.

The body means 42 defines a substantially continuous imperforate sidewall portion, and it will be noted that a plane passing through thelongitudinal axis of the draft tube will intercept the inner and outersurfaces of the body means 42 so as to define straight lines. Thesestraight lines of course extend axially of the body means and aredisposed substantially parallel with the adjacent axially extendingportions of the draft tube. A cylindrical body means may be employed aslong as the taper or divergence of the draft tube is not too great.Where the length of the body means 42 is not too long and the divergenceof the draft tube is less than approximately 5%, the body means may becylindrical. If the divergence of the draft tube is greater than 5%, adifferent shaped body means may be employed as hereinafter described.

The body means is fixedly supported in the upper part of the draft tubeby a first plurality of tubular support members 46 shown as being fourin number and equally spaced about the body means, these support membersextending between the outer surface of body means 42 and the innersurface of the draft tube. Four similar support members 48 are providedbeneath members 46. The number and size of the support members should bethe minimum required to support the assembled apparatus in the operatingenvironment and to prevent any significant vibration thereof. Thevarious components including the draft tube, the body means and theassoci-- ated support members may comprise a welded assembly ofstructural steel or other suitable materials.

It should be noted with the arrangement described above, the axiallyextending portions of the body means are oriented to be approximately inline with the fiow of water from the runner when it is operating at itsdesign load.

The fiow control means is located at a specific position relative to therunner, and its positioning and dimensions may be more clearlyunderstood from a consideration of FIGS. 1 and 4. The distance x isintended to denote the distance from the upper end of body means 42 tothe top of the draft tube 40. This distance is critical for properoperation of the apparatus and should be in a range. of approximately20% to approximately 50% of the inner diameter of the draft tube at thetop portion thereof as indicated by D.

The inner diameter d and the lengthl of the bore formed through the bodymeans also has a critical relationship to the distance D. In order toafford proper operation of the apparatus, d should be in the range ofapproximately 20% to approximately 70% of D, and I should be in therange of approximately 20% to approximately 50% of D.

In FIG. 4, the body means 42 illustrated in solid lines indicates theminimum dimensions of the variable x, d and l. The phantom lineillustration of the body means illustrates the maximum distances ofthese various variable quantities. It will be understood that variouscombinations of sizes in between these limits can be provided. Thesevariables will depend on each particular turbine installation and on thedesign of the water passages of the turbine. However, these variablesmust be within the critical ranges as discussed above in order toprovide the new and improved results of the presentv invention.

It will also be noted that the thickness of the wall portion of bodymeans 42 should be of the minimum required to prevent any significantvibration or weakening of the apparatus, and this wall thickness asindicated by t in FIG. 3 is many time less than :the inner diameter ofthe bore 44 extending through the body means.

times less than the inner diameter .of bore 44.

Referring now to FIGS. 5 and 6, a modification of the invention isillustrated wherein the draft tube and the, flow control means issubstantially identical with that pre-.

viously described, and similar parts have been giventhe same referencenumerals primed. The only difference in this particular modification isthe fact that the support members 46' are surrounded by streamliningmembers or portions 50, and support members 481are surrounded bystreamlining portions or members 52. Each of these streamlining membersis of substantially identical construction, and the details thereof areillustrated in FIG. 6.-

As seen in this figure, streamlining portion 50 includes a pair ofcomplementary members 54, 56 which are provided with semi-cylindricalinwardly facing cutouts 54' and 56' respectively which are adapted tofit about the outer surface of the associated support member 46.

Members 54 and 56 are held together by screws 58 whichl are adapted tobe threaded through aligned openings provided in the two adjacentmembers.

The streamlining portions 50 as well as 52 are fitted about theassociated support members such that they are freely rotatable ormovable thereabout. With this. ar-

rangement, the streamlining members can automatically move into positionso as to alford maximum resistance to flow thereabout. Accordingly, thestreamlining members will rotate about the associated support membersunder the influence of the flowing water so as to conform with;

previously described and have been given the same reference numeralsprimed. In this modification, the draft tube 60 is modified from thatpreviously illustrated in that it diverges at a greater rate in adownward direction, or in other words more than approximately 5%.

vided.

Body means 62 is substantially frusto-conical in configuration as seenmost clearly in FIG. 9, it being noted that a bore 63 is formedcentrally therethrough and of As in the pre-:

course is of frusto-conical configuration. vious modification, bodymeans 62 is fixedly supported in the central part of the upper end ofthe draft tube and is disposed substantially concentrically therewith.

a longitudinally extending axis which coincides with the axis of thedraft tube.

Body means 62 is fixedly mounted in position by a first plurality ofsupport members 64 and a second plurality of support members 66 similarto those previously described. I

It will be noted as seen particularly in FIG. 9 that the outer and innersurfaces of the body means 62 are disposed at substantially the sameangle of divergence as the inner surface of the draft tube, and axiallyextending portions of the inner and outer surfaces of body means 62. areoriented so as to be approximately in line with the flow of water fromthe turbine runner when it is operating at its design load.

As in the previously described modification, the top part of the bodymeans is spaced below the top of the draft tube a distance within thesame ranges as the distance x described in connection with the previousmodifications.

It is con-. templated that this thickness will ordinarly be at least 50With this. type of arrangement, a modified body means 62 is pro-' Itwill. be understood that body means 62 is symmetrical about.

In addition, the inner diameter at the upper end of the bore within thebody means 62 is within the same ranges as the distance d previouslydiscussed, and the length of the bore within body means 62 is alsowithin the ranges of l as previously described.

Referring now to FIGS. and 11, a further modified form of the inventionis illustrated which is similar to that shown in FIGS. 79. The drafttube, body means and support members are substantially the same as thosepreviously illustrated and are provided with the same reference numeralsprimed. The only difference in the modifications shown in FIGS. 10 and11 is the provision of a support member 70 which is substituted for oneof the support members 64, this support member 70 being hollow andterminating in a nozzle 72 having a discharge 74 facing in a downwarddirection. This discharge nozzle is located in the central upper portionof the bore within body means 62'.

Hollow support member 74 is adapted to be connected to a suitable sourceof external gas pressure such as air under pressure which can becontrolled by a suitable valve and the like so as to admit gas or airinto the central upper portion of the bore within the body means so asto cushion shocks and to smooth out flow of liquid through the fiowcontrol means. i

It is apparent from the foregoing that there is provided according tothe present invention new and novel hydraulic turbine apparatusincluding an improved draft tube construction which results in asubstantial reduction of noise, vibration, pressure surges and powerswings by providing flow control means which stabilizes the flow andreduces the vortex within the moving liquid. The performance of theturbine is not appreciably affected at design load and is substantiallyimproved at loads above and below the design load with no appreciableloss in power or efficiency. The apparatus is quite simple andinexpensive in construction, yet is very efficient and reliable inoperation.

As this invention may be embodied in several forms without departingfrom the spirit or essential characteristics thereof, the presentembodiment is therefore illustrative and not restrictive, and since thescope of the invention is defined by the appended claims, all changesthat fall within the metes and bounds of the claims or that form theirfunctional as well as conjointly cooperative equivalents are thereforeintended to be embraced by those claims.

I claim: 7

1. Hydraulic turbine apparatus comprising a runner, a draft tubeoperatively associated with said runner and having a certain innerdiameter at its upper portion, the top of said draft tube being disposedbelow the under surface of said runner so that the runner does notextend into said draft tube, flow control means comprising a generallyannular body means defining a central bore therethrough, said body meansbeing fixed in the upper part of said draft tube and being spaced fromthe inner surface thereof and in concentric relationship therewith, theupper part of said body means being spaced below the top of said drafttube in a direction away from said runner a distance which is at leastapproximately 20% of said inner diameter of the top portion of the drafttube.

2. Apparatus as defined in claim 1, wherein said distance is no greaterthan approximately 50% of the inner diameter of the top portion of thedraft tube.

3. Hydraulic turbine apparatus including a runner, a draft tubeoperatively associated with said runner and having a certain innerdiameter at the top portion thereof, the top of said draft tube beingdisposed below the under surface of said runner so that the runner doesnot extend into said draft tube, flow control means including a tubularbody means defining a central bore formed therethrough, said centralbore having an inner diameter and a length, the upper part of said bodymeans being spaced below the top of said draft tube in a direction awayfrom said runner a distance within the range of approximately 20% toapproximately 50% of the inner diameter of the top portion of the drafttube, the inner diameter of said bore being Within the range ofapproximately 20% to approximately 70% of the inner diameter of saidinner diameter at the top portion of the draft tube.

4. Apparatus as defined in claim 3 wherein the length of said bore iswithin the range of approximately 20% to approximately 50% of the innerdiameter at the top portion of the draft tube.

5. Hydraulic turbine apparatus including a runner, a draft tubeoperatively associated with said runner and having a certain innerdiameter at the top portion thereof, the top of said draft tube beingdisposed below the under surface of said runner so that the runner doesnot extend into said draft tube, said draft tube being elongated about alongitudinal axis, flow control means comprising an annular body meansformed symmetrically about a longitudinally extending axis whichcoincides with the axis of said draft tube, said body means being spacedfrom the inner surface of said draft tube and being fixed within theupper part of the draft tube, said body means including a substantiallycontinuous imperforate side Wall portion, said body means defining acentral bore formed therethrough having a certain inner diameter andlength, the thickness of the side wall portion of said body means beingmany times less than the inner diameter and length of said bore, the topof said body means being spaced below the top of the draft tube in adirection away from said runner a distance within the range ofapproximately 20% to approximately 50% of the inner diameter at the topportion of the draft tube, the inner diameter of said bore being withinthe range of approximately 20% to approximately 70% of the innerdiameter at the top portion of the draft tube, and the length of saidbore being within the range of approximately 20% to approximately 5 0%of the inner diameter at the top portion of the draft tube.

6. Hydraulic turbine apparatus including a runner, a draft tubeoperatively associated with said runner and having a certain innerdiameter at the top portion thereof, the top 'of said draft tube beingdisposed below the under surface of said runner so that the runner doesnot extend into said draft tube, flow control means comprising asubstantially cylindrical ring means supported in fixed relationship inthe upper part of the draft tube and being spaced from the inner surfaceof the draft tube and in substantially concentric relationshiptherewith, said cylindrical ring means defining a bore formedtherethrough having a certain inner diameter and length, the upper endof said cylindrical ring means being spaced below the top of said drafttube in a direction away from said runner a distance within the range ofapproximately 20% to approximately 50% of said inner diameter at the topportion of the draft tube, the inner diameter of said bore being withinthe range of approximately 20% to approximately 70% of said innerdiameter at the top portion of the draft tube, and the length of saidbore being in the range of approximately 20% to approximately 50% of theinner diameter at the top portion of the draft tube.

7. Hydraulic turbine apparatus comprising a runner, a draft tubeoperatively associated with said runner, said draft tube diverging in adownward direction at a rate greater than five percent, the top of saiddraft tube being disposed below the under surface of said runner so thatthe runner does not extend into said draft tube, flow control meanscomprising a substantially frustocomically shaped body means defining acentral bore therethrough, said flow control means being fixed in theupper part of the draft tube and spaced from the inner surface of thedraft tube and in substantially concentric relationship therewith, theupper part of said flow control means being spaced below the top of saiddraft tube in a direction away from-said runner a distance which is atleast approximately twenty percent of the inner diameter of the topportion of the draft tube.

8. Hydraulic turbine apparatusrcompn'sing a runner, a draft tubeoperatively associated with said runner and having a certain innerdiameter at the top portion thereof, the top of said draft tube beingdisposed below the under surface of said runner so that the runner doesnot extend into said draft tube, flow control means comprising'asubstantially frusto-conically shaped ring member defining a boretherethrough, said ring member being fixedly mounted within the upperpart of the draft tube and spaced from the inner surface of the drafttube and in substantially concentric relationship therewith, the borethrough said ring member having an inner diameter at the top part of thering member and having a certain length, the upper part of said ringmember being spaced below the top of said draft tube in a direction awayfrom said runner a distance within the range of approximately 20% toapproximately 50% of said inner diameter at the top portion of the drafttube, said inner diameter of the bore being within the range ofapproximately 20% to approximately 70% of the inner diameter at the topportion of the draft tube, and the length of said bore being within therange of approximately 20% to approximately 50% of said inner diameterat the top portion of the draft tube.

9. In the draft tube of a hydraulic turbine, flow control meansincluding a generally tubular body means spaced from the inner surfaceof said draft tube and in substantially concentric relationshiptherewith, support means extending from the inner surface of said drafttube to said body means for fixedly mounting the body means in operativeposition, and streamlining means having a top of said draft tube beingdisposed below the under surface of said runner so that the runner doesnot extend,

into said draft tube, tubular body means fixedly mounted l in the upperpart of the draft tube and spaced from the inner surface of the drafttube and substantially concentrically therewith, said tubular body meansbeing, spaced below the top-of said draft tube in a direction away fromsaid runner, said body means being open at both the top and bottom endsthereof and defining a central bore extending therethrough, and meansfor intro- I ducing gas into the central upper portion of said boredefined within the body means.

References Cited by the Examiner UNITED STATES PATENTS 2,507,796 5/1950Martin 253--117 3,051,441 8/ 1962 Sproule 25 3-1 17 FOREIGN PATENTS1,162,872 4/ 1958 France.

839,964 6/ 1960 Great Britain.

EDGAR W. GEOGHEGAN, Primary Examiner.

EVERETTE A. POWELL, JR., Examiner.

1. A HYDRAULIC TURBINE APPARATUS COMPRISING A RUNNER A DRAFT TUBEOPERATIVELY ASSOCIATED WITH SAID RUNNER AND HAVING A CERTAIN INNERDIAMETER AT ITS UPPER PORTION, THE TOP OF SAID DRAFT TUBE BEING DISPOSEDBELOW THE UNDER SURFACE OF SAID RUNNER SO THAT THE RUNNER DOES NOTEXTEND INTO SAID DRAFT TUBE, FLOW CONTROL MEANS COMPRISING ATHERETHROUGH, SAID BODY MEANS BEING FIXED IN THE UPPER PART OF SAIDDRAFT TUBE AND BEING SPACED FROM THE INNER SURFACE THEREOF AND INCONCENTRIC RELATIONSHIP THEREWITH, THE UPPER PART OF SAID BODY MEANSBEING SPACED BELOW THE TOP OF SAID DRAFT TUBE IN A DIRECTION AWAY FROMSAID RUNNER A DISTANCE WHICH IS AT LEST APPROXIMATELY 20% OF SAID INNERDIAMETER OF THE TOP PORTION OF THE DRAFT TUBE.